We plan to work on some other MNG and JNG supporting tools,
but they fall in the vaporware category right now.

A "git" repository for pmt tools is available. You can access it by
cloning git://git.code.sf.net/p/pmt/code.
At present, the pngcrush application is located in the "pngcrush"
branch, pngzop is in the "pngzop" branch, and the png2uri script is in
the "png2uri" branch of the "pmt" repository.